Roll mill and temperature-controlled roll

ABSTRACT

Apparatus of the type used to work or calender materials such as rubber, plastic and the like between parallel-spaced rolls. To facilitate temperature control, a roll has internal heating elements and axially extending passageways, one centrally of the roll and others radially outward from the heating elements for carrying a flow of cooling fluid such as air. The outer passageways are located so that a flow of cooling fluid therethrough will provide a thermal barrier to the flow of heat from the heating means to the roll periphery and will produce a relatively uniform effect upon the temperature throughout the roll surface.

United States Patent [72] Inventor James T. Matsuoka Brecksville, Ohio [2|] AppLNo. 877,235 [22] Filed Nov. 17,1969 Patented Oct.l9, 1971 [73] Assignee Intercole Automation, Inc.

Cleveland, Ohio [54] ROLL MILL AND TEMPERATURE-CONTROLLED ROLL 2 Claims, 6 Drawing Figs.

[52] U.S.Cl 219/469 [51] 05b 1/02 FieldofSearch 219/469, 47]

[ 56] References Cited UNITED STATES PATENTS 3,242,3[6 3/1966 Cranskens 2l9/47 1 3,401,626 9/1968 Amalfitano 219/469 3,471,683 10/1969 Bogue 219/469 FOREIGN PATENTS 1,462,089 12/1965 France 219/469 Primary ExaminerBernard A. Gilheany Assistant Examiner-F. E. Bell Att0rneyWatts, Hoffmann, Fisher & Heinke ABSTRACT: Apparatus of the type used to work or calender materials such as rubber, plastic and the like between parallelspaced rolls. To facilitate temperature control, a roll has internal heating elements and axially extending passageways, one centrally of the roll and others radially outward from the heating elements for carrying a flow of cooling fluid such as air. The outer passageways are located so that a flow of cooling fluid therethrough will provide a thermal barrier to the flow of heat from the heating means to the roll periphery and will produce a relatively uniform effect upon the temperature throughout the roll surface.

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EM P M WM T m M J ATTORNEYS.

ROLL MILL AND TEMPERATURE-CONTROLLED ROLL This invention relates to apparatus for working or calendering materials, such as rubber, plastic and the like, and especially to a temperature-controlled roll for a mill or calender.

In mills or calenders of the type used in the rubber and plastic industry, material is worked or formed into sheets between power-driven rolls or mills of calenders. In such operations, it is desirable to control the temperature of the rolls so that the material being processed can be properly worked or formed to a desired state.

It is an object of the present invention to provide a roll for use with mills or calenders of the type described above, with improved temperature control means to assure that accurate and uniform temperatures can be established at the peripheral surface of the roll.

Another object of this invention is to provide improved apparatus of the type used to work or calender materials such as rubber, plastic and the like having one or more rolls with improved temperature control means for providing accurate and uniform temperatures at the peripheral surface of the roll or rolls.

In the present invention, improved roll construction facilitates rapid and effective heat input and heat removal to and from the roll and hence provides improved flexibility of temperature control at the periphery of the roll. The improved construction further assures a substantial equal temperature throughout the roll surface. Heat is uniformly distributed from a central heat source or sources radially outward to the peripheral surface of the roll, while heat losses to journal portions of the roll are minimized. As a result, heating efficiency and response time are improved. Maximum colling is facilitated by providing passages for a straight throughflow of air through a body portion of the roll. In a preferred embodiment the passages are located to provide both a central zone of cooling and a zone that encircles the source of heat. In particular, individual passageways are located to (a) produce an effective thermal barrier to heat conducted from the central portion of the roll body toward the periphery, and (b) to assure that the local cooling effect produced at the passageways is diffused at the periphery of the roll so that a uniform, controlled, temperature results. Furthermore, provision is made for supplying all passageways from a central supplying passage through a journal portion of each roll and for exhausting the flow in the same manner at the opposite end of the roll. This results in an efficient cooling flow that has a cooling effect on the roll bearings and permits a direct and reliable connection between a source of air and the rolls remote from the central working area.

The above and other objects, features and advantages of this invention will become more apparent as the invention becomes better understood, by reference to the following detailed description, when considered in connection with the accompanying drawings, in which:

FIG. 1 is a front elevational view of a roll mill embodying the present invention;

FIGS. 2 and 2A taken together form a composite view of the roll mill of FIG. 1 partially in section and on an enlarged scale, showing constructional details of a roll embodying the present invention;

FIG. 3 is a sectional view of the roll of FIG. 2, taken along the line 3-3;

FIG. 4 is an end elevational view of the roll mill of FIG. 1, with parts removed, as viewed from the right-hand side; and

FIG. 5 is a schematic diagram illustrating a system for supplying cooling air to the rolls of the mill of FIG. 1.

Referring now to the drawings, a roll mill is shown for working material, such as rubber, plastic and the like, between two horizontal and parallel driven rolls 12, 14. Two spaced end frames l6, 18 of the mill are mounted on a suitable base 20 and support opposite ends of the rolls in journal boxes. As shown, journal boxes 22, 23 rotatably support the roll 12 and journal boxes 24, 25 support the roll 14. Journal boxes 22 and 23 are movable laterally within the end frames 16, 18 to adjust the space between the rolls 12 and 14. Adjustment is facilitated by thrust screws 28, 29 in the end frames, which bear against each movable journal box to limit the lateral spacing.

The roll 12 is directly driven at one end by a chain wheel 30 and the roll 12 is driven by the roll 14 through connecting gears 32, 33 carried, respectively, by the rolls I2, 14. The chain wheel 30 is driven by a chain 35 from an electric motor and drive sprocket (not shown) beneath the base 20. The chain wheel, connecting gears and chain are covered by a shroud 36 that extends upward from the base 20. In larger mills, the rolls are typically gear-driven by an electric motor, through a gear reducer. An overhead cradle safety unit 37 with a safety switch to the power drive of the roll mill is supported on the end frames 16, 18 above the rolls 12, I4.

At the end of each roll 12, I4 opposite from the drive, a slip ring unit 40 and air seal 41 is provided to carry current to heating elements of the rolls and to supply air to the interior of the rolls. The slipring units and air seals are within a housing 44 carried by the base 20. Appropriate related apparatus, including an air regulator 45, an air gauge 46, conduits and the like, are associated with the housing 44, slipring units and air seals. Also, conventional work guides 50, 51 are supported by associated brackets 52, 53 on the end frames I6, 18 at opposite ends of a central working area of each roll l2, 14.

Referring now particularly to FIGS. 2, 2A and 3, the roll I4 is shown in detail, and comprises a cylindrical roll body 56 that forms a central body portion of the roll, and two end parts 58, 59 that are supported in the journal boxes 24, 25. Each end part includes an end flange portion 580, 59a and a journal portion 58b, 59b. The construction of both rolls l2 and 14 is identical and only the construction of roll l4 and related parts will be described in detail. The end flange portions 58a, 59a of the end parts abut flat, opposite, end surfaces 61, 62, respectively, of the cylindrical roll body 56 and are secured to the roll body by machine screws 64. Each journal portion 58b, 59b is supported by bearings 66, 67 in the journal boxes 24, 25, respectively. The bearings 66 are retained by a spacer 68 and retaining nut 69 on the journal portion 58b, and the bearings 67 are retained by a spacer 70 and retaining nut 71 on the journal portion 59b. Inside and outside seals 74, 75 are associated with the journal box 24 and inside and outside seals 76, 77 are associated with the journal box 25, enclosing the bearings 66, 67. Each end part 58, 59 has a central passageway 80, 81, respectively, extending longitudinally the length of the end part and terminating at the respective flange portion in a relatively large cavity 80a and 81a. Each flange portion has a radially disposed, annular, seating surface 58c, 590 that abuts the adjacent end surface 61, 62 of the central roll body portion. An annular groove or recess 84 is formed in the seating surface 580 and an annular groove or recess 85 is formed in the seating surface 59s to reduce the contact area between the end parts 58, 59 and the central roll body part 56 and thereby minimize heat conduction between the parts.

The cylindrical roll body 56 has a central passageway 88 along the longitudinal central axis to carry a through flow of cooling air, three intermediate passageways 90a, b, c centrally of the roll body for receiving heaters, and a plurality of passageways 92 (at least six and preferably more-twelve passageways 921 I being provided in the embodiment shown) located radially outward from and in a circular path surrounding the intermediate passageways 90, for carrying a through flow of cooling air. The passageways 88, 90 and 92 extend through the entire length of the cylindrical roll body 56 and communicate at opposite ends with the cavity portions 80a and 81a of the end parts 58, 59. An electrical resistance heating element 94 is located in each intermediate passageway 90 and serves to heat the central roll body 56 to a desired temperature. Insulation plugs 95 are in the passageways 90 at opposite ends of each heating element to insulate the heaters from the flow of cooling air. The central passageway 88, by providing for a central airflow, prevents a buildup of heat from the heating elements at the center of the roll and aids in removing heat from the roll which otherwise would flow toward the periphery, and thereby improves the speed at which the temperature of the roll periphery responds to a flow of cooling air through the roll. The plurality of passageways 92 are relatively close together to create a greater passageway area than conductive area in a circular path between the heating elements and the outer periphery of the roll. That is, the average diameter of the passageways 92 is greater than the average distance between adjacent passageways 92. Thus, the passageways creates an effective barrier to the outward flow of heat when air is passed through. Preferably, the passageways 92 are of equal diameter and spaced uniformly from one another a distance less than the diameter of the passageways. In addition, each passageway 92 is spaced radially inward from the peripheral surface 96 a distance greater than the diameter of the passageways and preferably a distance at least twice the diameter of the passageways, to provide sufficient distance to the roll periphery relative to the cross-sectional area of the passageways 92 so that the cooling effect at the periphery of the roll from the circulation of air through the passageways in substantially uniform over the entire surface. The provision of at least six equally spaced passageways 92 is necessary to assure, with the relationship of the spacing and diameter that is specified, adequate and uniform cooling and at the same time maintain adequate roll strength.

To facilitate supplying electric current and air to the rolls 12, 14, a journal extension 102 is secured to the end part 58 of the roll 14 and an identical extension 103 is secured to the corresponding end part of the roll 12. Since the journal extensions, associated slipring units and air seals are identical for both rolls, only the structure on the roll 14 will be described in detail. The journal extension 102 is secured on the end part 58 of the roll 14 by machine screws 105 that extend through a flange portion 102a of the journal extension. Electrical leads 106 from the heating elements 94 and leads 107 from a thermocouple 108 imbedded within the roll body 56 extend through the passage 80. The leads extend through apertures in the flange 102, one such aperture being shown at 110 for the lead 107. The leads are connected to a terminal plate 112 associated with the slipring current distributor 40, both of which are carried on the journal extension 102. The slipring current distributor is connected to an external source of current, providing an electrical connection between the rotating heaters and thermocouple and the stationary current input. The journal extension 102 has a central passage 114 that receives the rotary union 41, which is connected to a source of air under pressure.

Air under pressure is supplied to the rolls 12 and 14 through the rotary unions 41 from a pneumatic system diagrammatically shown in FIG. 5. Factory air, typically under pressures between 30 to 100 pounds per square inch gauge, is supplied through a conduit 116 and pilot operated regular 118, to two parallel conduits 119, 120. The air may be supplied at various rates, typically up to about 150 cubic feet per minute. The conduits 119 and 120 each include, respectively, a solenoid valve 122, 123 and a bypass line 124, 125 each with an adjustable restriction 126, 127. The parallel conduits terminate at the respective rotary unions 41 to the rolls 12 and 14.

ln operation, the rolls 12 and 14 are counter rotated by the chain wheel 30 and connecting gears 32, 33 to work material between the rolls in a well-known manner. The temperature of the roll 12 and 14 (i.e., of the central cylindrical roll body portions) is controlled by electrically energizing the heating elements 94 or by providing a flow of air through the passageways 88 and 92. The heat output produced by the heating elements can be controlled by adjusting the current supplied thereto in a known manner, or by cyclically energizing the elements at a rated load. The rate of cooling is controlled by varying the flow of air through the passageways 88 and 92 under the control of the solenoid valves 122 and 123 and by varying the rate of flow of air through the parallel con duits 119, 120 by the regulator 118. Typically, either the heaters are energized or air is forced through the passages 88 and 92 alternately, rather than utilizing both heating and cooling simultaneously, to achieve and maintain a desired temperature, which tends to vary under the influence of outside factors such as the nature of the material being worked and the rate at which the work is being performed. The roll temperature can be automatically maintained by controlling the heaters and air control valves with a thermostat operated from the thermocouple 108.

Heat introduced to the interior of each roll from the heating elements 94 is conducted toward the periphery of the roll and raises the temperature of the roll or maintains an elevated temperature. Residual heat within the roll causes a substantial lag in the time between the deenergization of the heating elements and a corresponding drop in surface temperature of the roll. This time lag is substantially reduced by the flow of cooling air through the passages 88 and 92, which lowers the central roll temperature and interrupts the outward flow of heat to the roll periphery. At the same time, heat from adjacent the periphery of the roll is extracted by the flow of air through the passageways 92 to lower the roll surface temperature or establish an equilibrium temperature. Air flowing through the passageways 88 and 92 of each roll is discharged through the end part 59 on the opposite side of the central roll body portion from the slipring unit and air supply connection. Typically, the roll surfaces are maintained at temperatures between 500 to 800 F. by the control of the heating elements and flow of air through the passageways 88 and 92.

While a preferred embodiment of this invention has been described in detail, it will be readily apparent that various modifications or alternations may be made therein without departing from the spirit and scope of the invention. For example, it will be apparent that the rolls and roll structure are equally suitable for use in calendering apparatus and that the temperature of any number of rolls of an apparatus can be controlled in the manner disclosed.

What is claimed is:

1. An electrically heated and air-cooled roll for a rubber mill, calender or the like comprising a cylindrical roll body, an end flange and journal secured to the roll body at each end, said end'flanges and said roll body having facing surfaces in abutting relationship, at least one of said facing surfaces at each end of the roll body being in part recessed to reduce the contact area and thermal conductivity between said roll body and end flanges, a central axial passageway through the roll body small in diameter relative to the roll diameter, at least three axially extending intermediate passageways through the roll body adjacent the central passageway and equally spaced from and about the central passageway, at least six additional axially extending passageways through the roll body located radially outward from said intermediate passageways and equally spaced from each other and uniformly spaced from the periphery of the roll body, the diameters of said additional passageways being equal to each other and greater than the distance between adjacent ones of said additional passageways to create an effective heat control zone between the intermediate passageways and the periphery of the roll body, and the distance from each said additional passageway to the periphery of the roll body being at least twice the diameter of said additional passageways to provide sufficient radial distance relative to the cross-sectional area of the additional passageways that the cooling effect at the periphery of the roll is substantially uniform throughout, an electric heater in each of said intermediate passageways, and a passageway in each end flange and journal communicating with said passageways extending through the roll body and adapted to carry electrical connections to said heaters and air for said central and said additional passageways.

2. ln apparatus of the type used to work or calender materials such as rubber, plastic and the like: a frame; a plurality of rolls supported by said frame for rotation, each about a central axis and located parallel and adjacent one to another, each said roll comprising a cylindrical roll body, an end flange and journal of reduced diameter secured to the roll body at each end, said end flanges and said roll body having facing radial surfaces in abutting relationship, at least one of said facing surfaces at each end of the roll body being in part recessed to reduce the contact area and thermal conductivity between said roll body and end flanges, a central axial passageway through the roll body small in diameter relative to the roll diameter, at least three axially extending intermediate passageways through the roll body adjacent the central passageway and equally spaced from and about the central passageway, at least six additional axially extending passageways through the roll body located radially outward from said intermediate passageways and equally spaced from each other and unifonnly spaced from the periphery of the roll body, the diameters of said additional passageways being equal to each other and greater than the distance between adjacent ones of said additional passageways to create an effective heat control zone between the intermediate passageways and the periphery of the roll body, and the distance from each said additional passageway to the periphery of the roll boy being at least twice the diameter of said additional passageways to provide sufficient radial distance relative to the spacing between the passageways that the cooling effect at the periphery of the roll is substantially uniform throughout; an electric heater in each of said intermediate passageways; a central passageway through each of said journal portions opening externally of the respective roll adjacent the outer ends of the journal portions and communicating with said plural passageways at the inner ends and adapted to carry electrical connections to said heaters and air for said central and said additional passageways; means at the outer end of one journal portion of each roll for connecting the central passageway thereof to a source of air under pressure for providing a throughflow of air from one end of the roll to the other without a return flow; a thermocouple in said central body portion of each roll; means carried by a journal portion of each roll for electrically connecting said electric heater and said thermocouple to electrical circuitry external to said rolls; and means to control the supply of air to said rolls to affect the temperature at the periphery of the central body portion. 

1. An electrically heated and air-cooled roll for a rubber mill, calender or the like comprising a cylindrical roll body, an end flange and journal secured to the roll body at each end, said end flanges and said roll body having facing surfaces in abutting relationship, at least one of said facing surfaces at each end of the roll body being in part recessed to reduce the contact area and thermal conductivity between said roll body and end flanges, a central axial passageway through the roll body small in diameter relative to the roll diameter, at least three axially extending intermediate passageways through the roll body adjacent the central passageway and equally spaced from and about the central passageway, at least six additional axially extending passageways through the roll body located radially outward from said intermediate passageways and equally spaced from each other and uniformly spaced from the periphery of the roll body, the diameters of said additional passageways being equal to each other and greater than the distance between adjacent ones of said additional passageways to create an effective heat control zone between the intermediate passageways and the periphery of the roll body, and the distance from each said additional passageway to the periphery of the roll body being at least twice the diameter of said additional passageways to provide sufficient radial distance relative to the cross-sectional area of the additional passageways that the cooling effect at the periphery of the roll is substantially uniform throughout, an electric heater in each of said intermediate passageways, and a passageway in each end flange and journal communicating with said passageways extending through the roll body and adapted to carry electrical connections to said heaters and air for said central and said additional passageways.
 2. In apparatus of the type used to work or calender materials such as rubber, plastic and the like: a frame; a plurality of rolls supported by said frame for rotation, each about a central axis and located parallel and adjacent one to another, each said roll comprising a cylindrical roll body, an end flange and journal of reduced diameter secured to the roll body at each end, said end flanges and said roll body having facing radial surfaces in abutting relationship, at least one of said facing surfaces at each end of the roll body being in part recessed to reduce the contact area and thermal conductivity between said roll body and end flanges, a central axial passageway through the roll body small in diameter relative to the roll diameter, at least three axially extending intermediate passageways through the roll body adjacent the central passageway and equally spaced from and about the central passageway, at least six additional axially extending passageways through the roll body located radially outward from said intermediate passageways and equally spaced from each other and uniformly spaced from the periphery of the roll body, the diameters of said additional passageways being equal to each other and greater than the distance between adjacent ones of said additional passageways to create an effective heat control zone between the intermediate passageways and the periphery of the roll body, and the distance from each said additional passageway to the periphery of the roll boy being at least twice the diameter of said additional passageways to provide sufficient radial distance relative to the spacing between the passageways that the cooling effect at the periphery of the roll is substantially uniform throughout; an electric heater in each of said intermediate passageways; a central passageway through each of said journal portions openinG externally of the respective roll adjacent the outer ends of the journal portions and communicating with said plural passageways at the inner ends and adapted to carry electrical connections to said heaters and air for said central and said additional passageways; means at the outer end of one journal portion of each roll for connecting the central passageway thereof to a source of air under pressure for providing a throughflow of air from one end of the roll to the other without a return flow; a thermocouple in said central body portion of each roll; means carried by a journal portion of each roll for electrically connecting said electric heater and said thermocouple to electrical circuitry external to said rolls; and means to control the supply of air to said rolls to affect the temperature at the periphery of the central body portion. 